On a wet Wednesday evening in Seoul, six government employees gather at the office to prepare for a late-night patrol. The mission is as simple as it is counterintuitive: to find children who are studying after 10 p.m. And stop them.

In South Korea, it has come to this. To reduce the country's addiction to private, after-hours tutoring academies (called hagwons), the authorities have begun enforcing a curfew — even paying citizens bounties to turn in violators. ...

But cramming is deeply embedded in Asia, where top grades — and often nothing else — have long been prized as essential for professional success. Before toothbrushes or printing presses, there were civil service exams that could make or break you. Chinese families have been hiring test-prep tutors since the 7th century. Modern-day South Korea has taken this competition to new extremes. In 2010, 74% of all students engaged in some kind of private after-school instruction, sometimes called shadow education, at an average cost of $2,600 per student for the year. There are more private instructors in South Korea than there are schoolteachers, and the most popular of them make millions of dollars a year from online and in-person classes. When Singapore's Education Minister was asked last year about his nation's reliance on private tutoring, he found one reason for hope: "We're not as bad as the Koreans."